define and use print format macros for mrb_int

For portability: %ld can't be used to print a 64-bit mrb_int on
WIN(32|64) because long is 32-bit wide.
fix the type of value that is returned by bit-shift expression.
 fix the type of value that is returned by bit-shift expression.
"Ax" is larger than 16-bit.
fix the type of value that is returned by bit-shift expression.
fix comment.
Merge pull request #1039 from crimsonwoods/fix_the_type_of_opcode

Fix the type of value that is returned by bit shift expression.
Make array.c and vm.c share value_move().
Add bitbucket git support.
Use mrb_str_cat() instead of mrb_str_cat2() as possible.
Rename API mrb_str_cat2() to mrb_str_cat_cstr(). This is for naming orthogonality. mrb_str_cat2() is also left for backward compatibility.
Set MRB_TT_MODULE to Module.
Add mruby-random mrbgem (no activation though)
Add double-quote
Merge pull request #1052 from matsumoto-r/add_mruby_random

Add mruby random
Merge pull request #1051 from monaka/pr-set-MRB_TT_MODULE-to-Module

Set MRB_TT_MODULE to Module.
Merge pull request #1050 from monaka/pr-cleanup-string.c-20130323

Clean up string.c
Merge pull request #1048 from monaka/pr-make-array.c-and-vm.c-share-value_move

Make array.c and vm.c share value_move().
Merge pull request #1049 from monaka/pr-bitbucket-git-support

Add bitbucket git support.
Add new API mrb_ptr_as_string().